clk: Introduce Kunit Tests for the framework

Let's test various parts of the rate-related clock API with the kunit
testing framework.

Cc: [e-mail]
Tested-by: Daniel Latypov <[e-mail]>
Suggested-by: Stephen Boyd <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/.kunitconfig

···
 CONFIG_KUNIT=y
 CONFIG_COMMON_CLK=y
+CONFIG_CLK_KUNIT_TEST=y
 CONFIG_CLK_GATE_KUNIT_TEST=y

drivers/clk/Kconfig

···
 source "drivers/clk/zynqmp/Kconfig"
 
 # Kunit test cases
+config CLK_KUNIT_TEST
+	tristate "Basic Clock Framework Kunit Tests" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Kunit tests for the common clock framework.
+
 config CLK_GATE_KUNIT_TEST
 	tristate "Basic gate type Kunit test" if !KUNIT_ALL_TESTS
 	depends on KUNIT

drivers/clk/Makefile

···
 # common clock types
 obj-$(CONFIG_HAVE_CLK)		+= clk-devres.o clk-bulk.o clkdev.o
 obj-$(CONFIG_COMMON_CLK)	+= clk.o
+obj-$(CONFIG_CLK_KUNIT_TEST)	+= clk_test.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-divider.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-fixed-factor.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-fixed-rate.o

drivers/clk/clk_test.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kunit test for clk rate management
+ */
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+
+/* Needed for clk_hw_get_clk() */
+#include "clk.h"
+
+#include <kunit/test.h>
+
+#define DUMMY_CLOCK_INIT_RATE	(42 * 1000 * 1000)
+#define DUMMY_CLOCK_RATE_1	(142 * 1000 * 1000)
+#define DUMMY_CLOCK_RATE_2	(242 * 1000 * 1000)
+
+struct clk_dummy_context {
+	struct clk_hw hw;
+	unsigned long rate;
+};
+
+static unsigned long clk_dummy_recalc_rate(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	struct clk_dummy_context *ctx =
+		container_of(hw, struct clk_dummy_context, hw);
+
+	return ctx->rate;
+}
+
+static int clk_dummy_determine_rate(struct clk_hw *hw,
+				    struct clk_rate_request *req)
+{
+	/* Just return the same rate without modifying it */
+	return 0;
+}
+
+static int clk_dummy_maximize_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
+{
+	/*
+	 * If there's a maximum set, always run the clock at the maximum
+	 * allowed.
+	 */
+	if (req->max_rate < ULONG_MAX)
+		req->rate = req->max_rate;
+
+	return 0;
+}
+
+static int clk_dummy_minimize_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
+{
+	/*
+	 * If there's a minimum set, always run the clock at the minimum
+	 * allowed.
+	 */
+	if (req->min_rate > 0)
+		req->rate = req->min_rate;
+
+	return 0;
+}
+
+static int clk_dummy_set_rate(struct clk_hw *hw,
+			      unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct clk_dummy_context *ctx =
+		container_of(hw, struct clk_dummy_context, hw);
+
+	ctx->rate = rate;
+	return 0;
+}
+
+static const struct clk_ops clk_dummy_rate_ops = {
+	.recalc_rate = clk_dummy_recalc_rate,
+	.determine_rate = clk_dummy_determine_rate,
+	.set_rate = clk_dummy_set_rate,
+};
+
+static const struct clk_ops clk_dummy_maximize_rate_ops = {
+	.recalc_rate = clk_dummy_recalc_rate,
+	.determine_rate = clk_dummy_maximize_rate,
+	.set_rate = clk_dummy_set_rate,
+};
+
+static const struct clk_ops clk_dummy_minimize_rate_ops = {
+	.recalc_rate = clk_dummy_recalc_rate,
+	.determine_rate = clk_dummy_minimize_rate,
+	.set_rate = clk_dummy_set_rate,
+};
+
+static int clk_test_init_with_ops(struct kunit *test, const struct clk_ops *ops)
+{
+	struct clk_dummy_context *ctx;
+	struct clk_init_data init = { };
+	int ret;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	ctx->rate = DUMMY_CLOCK_INIT_RATE;
+	test->priv = ctx;
+
+	init.name = "test_dummy_rate";
+	init.ops = ops;
+	ctx->hw.init = &init;
+
+	ret = clk_hw_register(NULL, &ctx->hw);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int clk_test_init(struct kunit *test)
+{
+	return clk_test_init_with_ops(test, &clk_dummy_rate_ops);
+}
+
+static int clk_maximize_test_init(struct kunit *test)
+{
+	return clk_test_init_with_ops(test, &clk_dummy_maximize_rate_ops);
+}
+
+static int clk_minimize_test_init(struct kunit *test)
+{
+	return clk_test_init_with_ops(test, &clk_dummy_minimize_rate_ops);
+}
+
+static void clk_test_exit(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+
+	clk_hw_unregister(&ctx->hw);
+}
+
+/*
+ * Test that the actual rate matches what is returned by clk_get_rate()
+ */
+static void clk_test_get_rate(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, ctx->rate);
+}
+
+/*
+ * Test that, after a call to clk_set_rate(), the rate returned by
+ * clk_get_rate() matches.
+ *
+ * This assumes that clk_ops.determine_rate or clk_ops.round_rate won't
+ * modify the requested rate, which is our case in clk_dummy_rate_ops.
+ */
+static void clk_test_set_get_rate(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
+}
+
+/*
+ * Test that, after several calls to clk_set_rate(), the rate returned
+ * by clk_get_rate() matches the last one.
+ *
+ * This assumes that clk_ops.determine_rate or clk_ops.round_rate won't
+ * modify the requested rate, which is our case in clk_dummy_rate_ops.
+ */
+static void clk_test_set_set_get_rate(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1),
+			0);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2);
+}
+
+/*
+ * Test that clk_round_rate and clk_set_rate are consitent and will
+ * return the same frequency.
+ */
+static void clk_test_round_set_get_rate(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rounded_rate, set_rate;
+
+	rounded_rate = clk_round_rate(clk, DUMMY_CLOCK_RATE_1);
+	KUNIT_ASSERT_GT(test, rounded_rate, 0);
+	KUNIT_EXPECT_EQ(test, rounded_rate, DUMMY_CLOCK_RATE_1);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1),
+			0);
+
+	set_rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, set_rate, 0);
+	KUNIT_EXPECT_EQ(test, rounded_rate, set_rate);
+}
+
+static struct kunit_case clk_test_cases[] = {
+	KUNIT_CASE(clk_test_get_rate),
+	KUNIT_CASE(clk_test_set_get_rate),
+	KUNIT_CASE(clk_test_set_set_get_rate),
+	KUNIT_CASE(clk_test_round_set_get_rate),
+	{}
+};
+
+static struct kunit_suite clk_test_suite = {
+	.name = "clk-test",
+	.init = clk_test_init,
+	.exit = clk_test_exit,
+	.test_cases = clk_test_cases,
+};
+
+/*
+ * Test that clk_set_rate_range won't return an error for a valid range
+ * and that it will make sure the rate of the clock is within the
+ * boundaries.
+ */
+static void clk_range_test_set_range(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
+	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
+}
+
+/*
+ * Test that calling clk_set_rate_range with a minimum rate higher than
+ * the maximum rate returns an error.
+ */
+static void clk_range_test_set_range_invalid(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+
+	KUNIT_EXPECT_LT(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1 + 1000,
+					   DUMMY_CLOCK_RATE_1),
+			0);
+}
+
+/*
+ * Test that users can't set multiple, disjoints, range that would be
+ * impossible to meet.
+ */
+static void clk_range_test_multiple_disjoints_range(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *user1, *user2;
+
+	user1 = clk_hw_get_clk(hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user1);
+
+	user2 = clk_hw_get_clk(hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user2);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user1, 1000, 2000),
+			0);
+
+	KUNIT_EXPECT_LT(test,
+			clk_set_rate_range(user2, 3000, 4000),
+			0);
+
+	clk_put(user2);
+	clk_put(user1);
+}
+
+/*
+ * Test that if our clock has some boundaries and we try to round a rate
+ * lower than the minimum, the returned rate won't be affected by the
+ * boundaries.
+ */
+static void clk_range_test_set_range_round_rate_lower(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_round_rate(clk, DUMMY_CLOCK_RATE_1 - 1000);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1 - 1000);
+}
+
+/*
+ * Test that if our clock has some boundaries and we try to set a rate
+ * lower than the minimum, we'll get an error.
+ */
+static void clk_range_test_set_range_set_rate_lower(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	KUNIT_ASSERT_LT(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1 - 1000),
+			0);
+}
+
+/*
+ * Test that if our clock has some boundaries and we try to round and
+ * set a rate lower than the minimum, the values won't be consistent
+ * between clk_round_rate() and clk_set_rate().
+ */
+static void clk_range_test_set_range_set_round_rate_consistent_lower(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	long rounded;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rounded = clk_round_rate(clk, DUMMY_CLOCK_RATE_1 - 1000);
+	KUNIT_ASSERT_GT(test, rounded, 0);
+
+	KUNIT_EXPECT_LT(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1 - 1000),
+			0);
+
+	KUNIT_EXPECT_NE(test, rounded, clk_get_rate(clk));
+}
+
+/*
+ * Test that if our clock has some boundaries and we try to round a rate
+ * higher than the maximum, the returned rate won't be affected by the
+ * boundaries.
+ */
+static void clk_range_test_set_range_round_rate_higher(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_round_rate(clk, DUMMY_CLOCK_RATE_2 + 1000);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2 + 1000);
+}
+
+/*
+ * Test that if our clock has some boundaries and we try to set a rate
+ * lower than the maximum, we'll get an error.
+ */
+static void clk_range_test_set_range_set_rate_higher(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	KUNIT_ASSERT_LT(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
+			0);
+}
+
+/*
+ * Test that if our clock has some boundaries and we try to round and
+ * set a rate higher than the maximum, the values won't be consistent
+ * between clk_round_rate() and clk_set_rate().
+ */
+static void clk_range_test_set_range_set_round_rate_consistent_higher(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	long rounded;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rounded = clk_round_rate(clk, DUMMY_CLOCK_RATE_2 + 1000);
+	KUNIT_ASSERT_GT(test, rounded, 0);
+
+	KUNIT_EXPECT_LT(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
+			0);
+
+	KUNIT_EXPECT_NE(test, rounded, clk_get_rate(clk));
+}
+
+/*
+ * Test that if our clock has a rate lower than the minimum set by a
+ * call to clk_set_rate_range(), the rate will be raised to match the
+ * new minimum.
+ *
+ * This assumes that clk_ops.determine_rate or clk_ops.round_rate won't
+ * modify the requested rate, which is our case in clk_dummy_rate_ops.
+ */
+static void clk_range_test_set_range_get_rate_raised(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1 - 1000),
+			0);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
+}
+
+/*
+ * Test that if our clock has a rate higher than the maximum set by a
+ * call to clk_set_rate_range(), the rate will be lowered to match the
+ * new maximum.
+ *
+ * This assumes that clk_ops.determine_rate or clk_ops.round_rate won't
+ * modify the requested rate, which is our case in clk_dummy_rate_ops.
+ */
+static void clk_range_test_set_range_get_rate_lowered(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
+			0);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2);
+}
+
+static struct kunit_case clk_range_test_cases[] = {
+	KUNIT_CASE(clk_range_test_set_range),
+	KUNIT_CASE(clk_range_test_set_range_invalid),
+	KUNIT_CASE(clk_range_test_multiple_disjoints_range),
+	KUNIT_CASE(clk_range_test_set_range_round_rate_lower),
+	KUNIT_CASE(clk_range_test_set_range_set_rate_lower),
+	KUNIT_CASE(clk_range_test_set_range_set_round_rate_consistent_lower),
+	KUNIT_CASE(clk_range_test_set_range_round_rate_higher),
+	KUNIT_CASE(clk_range_test_set_range_set_rate_higher),
+	KUNIT_CASE(clk_range_test_set_range_set_round_rate_consistent_higher),
+	KUNIT_CASE(clk_range_test_set_range_get_rate_raised),
+	KUNIT_CASE(clk_range_test_set_range_get_rate_lowered),
+	{}
+};
+
+static struct kunit_suite clk_range_test_suite = {
+	.name = "clk-range-test",
+	.init = clk_test_init,
+	.exit = clk_test_exit,
+	.test_cases = clk_range_test_cases,
+};
+
+/*
+ * Test that if:
+ * - we have several subsequent calls to clk_set_rate_range();
+ * - and we have a round_rate ops that always return the maximum
+ *   frequency allowed;
+ *
+ * The clock will run at the minimum of all maximum boundaries
+ * requested, even if those boundaries aren't there anymore.
+ */
+static void clk_range_test_set_range_rate_maximized(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
+			0);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2 - 1000),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2 - 1000);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2 - 1000);
+}
+
+/*
+ * Test that if:
+ * - we have several subsequent calls to clk_set_rate_range(), across
+ *   multiple users;
+ * - and we have a round_rate ops that always return the maximum
+ *   frequency allowed;
+ *
+ * The clock will run at the minimum of all maximum boundaries
+ * requested, even if those boundaries aren't there anymore.
+ */
+static void clk_range_test_multiple_set_range_rate_maximized(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	struct clk *user1, *user2;
+	unsigned long rate;
+
+	user1 = clk_hw_get_clk(hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user1);
+
+	user2 = clk_hw_get_clk(hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user2);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
+			0);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user1,
+					   0,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user2,
+					   0,
+					   DUMMY_CLOCK_RATE_1),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user2, 0, ULONG_MAX),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
+
+	clk_put(user2);
+	clk_put(user1);
+}
+
+static struct kunit_case clk_range_maximize_test_cases[] = {
+	KUNIT_CASE(clk_range_test_set_range_rate_maximized),
+	KUNIT_CASE(clk_range_test_multiple_set_range_rate_maximized),
+	{}
+};
+
+static struct kunit_suite clk_range_maximize_test_suite = {
+	.name = "clk-range-maximize-test",
+	.init = clk_maximize_test_init,
+	.exit = clk_test_exit,
+	.test_cases = clk_range_maximize_test_cases,
+};
+
+/*
+ * Test that if:
+ * - we have several subsequent calls to clk_set_rate_range()
+ * - and we have a round_rate ops that always return the minimum
+ *   frequency allowed;
+ *
+ * The clock will run at the maximum of all minimum boundaries
+ * requested, even if those boundaries aren't there anymore.
+ */
+static void clk_range_test_set_range_rate_minimized(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate(clk, DUMMY_CLOCK_RATE_1 - 1000),
+			0);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1 + 1000,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1 + 1000);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(clk,
+					   DUMMY_CLOCK_RATE_1,
+					   DUMMY_CLOCK_RATE_2),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1 + 1000);
+}
+
+/*
+ * Test that if:
+ * - we have several subsequent calls to clk_set_rate_range(), across
+ *   multiple users;
+ * - and we have a round_rate ops that always return the minimum
+ *   frequency allowed;
+ *
+ * The clock will run at the maximum of all minimum boundaries
+ * requested, even if those boundaries aren't there anymore.
+ */
+static void clk_range_test_multiple_set_range_rate_minimized(struct kunit *test)
+{
+	struct clk_dummy_context *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	struct clk *user1, *user2;
+	unsigned long rate;
+
+	user1 = clk_hw_get_clk(hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user1);
+
+	user2 = clk_hw_get_clk(hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user2);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user1,
+					   DUMMY_CLOCK_RATE_1,
+					   ULONG_MAX),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user2,
+					   DUMMY_CLOCK_RATE_2,
+					   ULONG_MAX),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2);
+
+	KUNIT_ASSERT_EQ(test,
+			clk_set_rate_range(user2, 0, ULONG_MAX),
+			0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2);
+
+	clk_put(user2);
+	clk_put(user1);
+}
+
+static struct kunit_case clk_range_minimize_test_cases[] = {
+	KUNIT_CASE(clk_range_test_set_range_rate_minimized),
+	KUNIT_CASE(clk_range_test_multiple_set_range_rate_minimized),
+	{}
+};
+
+static struct kunit_suite clk_range_minimize_test_suite = {
+	.name = "clk-range-minimize-test",
+	.init = clk_minimize_test_init,
+	.exit = clk_test_exit,
+	.test_cases = clk_range_minimize_test_cases,
+};
+
+kunit_test_suites(
+	&clk_test_suite,
+	&clk_range_test_suite,
+	&clk_range_maximize_test_suite,
+	&clk_range_minimize_test_suite
+);
+MODULE_LICENSE("GPL v2");